The present disclosure relates to an electric brake booster comprising an electric motor activating a booster piston acting on the master-cylinder when the brake pedal is activated, the booster piston being driven in the direction of the action of same on the master-cylinder by an electric motor linked to a mechanical transmission comprising a screw carried by the shaft of the motor and meshing with two symmetrical worm gears, each integral with a transmission shaft carrying a spur gear meshing with a rack of the booster piston, each shaft being housed in a bearing of the body of the brake booster.
Electric brake boosters of the type defined above are known. In these brake boosters, since the booster piston is driven symmetrically, balanced by two symmetrical transmissions relative to the plane passing through the axis of the booster piston and the drive screw, but since mechanically it is impossible to have perfect symmetry, in order to balance the drive by the two symmetrical transmissions, a clearance is left for the booster piston, that is to say for the racks, such that the booster piston can be positioned with the racks thereof so that the spur gears meshing therewith engage with the two racks in a balanced manner. However, the clearance that must be left for the booster piston is not suitable for the desirable accuracy of the operation of the brake booster or for the reliability thereof.
The object of the present disclosure is to perfect the guidance and the drive of the booster piston by the transmission linking the electric drive motor to the booster piston, and in particular to make it possible to reduce the clearance of the booster piston in the guiding seat thereof in the brake booster.